Check out C-More Red Dot Sight Low-poly 3D model on CGTrader for $14. High-quality mesh by RedWireframeStudios: 10194 polys, 5416 vertices. PBR, Textured, UV Mapped.
BLEND (Blender, filesize: 310 MB), OBJ (OBJ, filesize: 195 KB), FBX (Autodesk FBX, filesize: 391 KB), DAE (Collada, filesize: 331 KB), TEXTURES (Textures, filesize: 141 MB), SPP (Substance Painter, filesize: 206 MB)